Patterns of physical activity, adherence to a wearable activity tracker during a 12-week intervention and correlation between physical activity and function in individuals with hip and/or knee osteoarthritis

Abstract

BackgroundOsteoarthritis is a common joint disorder causing pain, functional limitations and an increased risk of comorbidities. Physical activity (PA) is the standard treatment but the majority of individuals with OA do not meet the recommended levels of PA (150 min/week). Monitoring PA with a wearable activity tracker (WAT) could promote PA but increased knowledge on PA patterns and usage of a WAT is needed. The aim of this study was to describe PA patterns and adherence to using a WAT among participants of working age with hip and/or knee OA, during a 12-week intervention. In addition, this study explores the correlation between baseline joint function and subsequent PA.MethodsIndividuals of working age with hip and/or knee OA (n = 75) who used a WAT, Fitbit Flex 2, for 12 weeks as part of an intervention in a cluster-randomized controlled trial were included. Participants were encouraged to monitor their PA in the Fitbit-app. An activity goal of 7,000 steps per day was set. Activity data was collected from the Fitbit. HOOS/KOOS were completed at baseline.ResultsParticipants walked on average 10 593 (SD 3431) steps per day, spent 336.0 (SD 249.9) minutes in moderate/vigorous (MV) PA and used the Fitbit for 88.4% of the 12-week intervention period. Steps per day decreased significantly over the 12 weeks (β-coefficient − 117, 95% CI -166 to -68, p = < 0.001) as well as MVPA per week (β-coefficient − 3.5, 95% CI -6.5 to -0.5, p = 0.02) and adherence to using the Fitbit (β-coefficient − 1.3, 95% CI -1.8 to -0.8, p = < 0.001). There were no significant correlations between baseline function (HOOS/KOOS) and subsequent PA.ConclusionThe majority of participants reached 7,000 steps/day and the recommended 150 minutes in MVPA per week. However, weekly PA decreased gradually over time. Adherence to using the Fitbit was high but also decreased during the intervention. Understanding PA-patterns and the use of a Fitbit to promote PA could be beneficial in tailoring interventions for individuals with hip and/or knee OA.Trial registrationThe C-RCT was registered in ClinicalTrials.gov. Registration number: NCT03354091. Registered 11/27/2017.